Exam #2 A+P

histology and skin

What detects an increase in temperature in the body?

Thermoreceptors.

2 layers of cutaneous membrane

dermis & epidermis

What are accesory structures of the skin?

Hair follicles, nails, sweat glands, and sebaceous glands.

Where does information from thermoreceptors go?

To the control center in the brain (hypothalamus).

What is the effector in thermoregulation when the body is too hot?

Sweat glands.

What is vasodilation?

The dilation of blood vessels to increase blood flow to the skin surface.

What is the feedback system called that helps the body return to normal temperature?

Negative feedback system.

What happens in response to cold temperatures?

Vasoconstriction of blood vessels in the skin.

What process occurs when the body temperature does not rise sufficiently after vasoconstriction?

Shivering.

What does vitamin D help increase the absorption of?

Calcium. (calcitrol)

What is the precursor to vitamin D produced in the skin?

Dehydrocholesterol.

What is the active form of vitamin D called?

Cholecalciferol (Vitamin D3).

What is the largest storage place for calcium in the body?

The skeletal system (bones).

What is the top layer of the skin called?

Epidermis.

What layer of skin contains blood vessels?

Dermis.

What type of tissue is the epidermis made from?

Stratified squamous epithelium.

What is keratin?

A fibrous protein that prevents water loss and adds strength to the skin.

What is the deepest layer of the epidermis?

Stratum basale.

What happens to cells as they move from the stratum basale to the surface?

They die and lose their nuclei.

What is the function of the stratum granulosum?

Contains keratinized cells providing waterproofing.

In what type of skin do we find the stratum lucidum?

Thick skin.

What is the outermost layer of the epidermis called?

Stratum corneum.

How long does it take for a keratinocyte to migrate through the layers of the epidermis?

About 40 to 45 days.

What type of cell is a Langerhans or dendritic cell?

A phagocytic immune cell.

What do Merkel cells do?

Detect light touch.

What do melanocytes produce?

Melanin.

What gives skin its color?

Melanin, carotene, and hemoglobin.

What is erythema?

Increased redness of the skin.

What is pallor?

Decreased blood flow resulting in paler skin.

What is jaundice?

A yellowish appearance of the skin due to liver dysfunction.

What happens to the body when it loses heat?

Sweating and vasodilation of blood vessels.

What type of secretion do eccrine sweat glands produce?

A watery fluid.

What does apocrine secretion involve?

Thicker sweat associated with hair follicles.

What is sebum?

Oily secretion from sebaceous glands.

What is the most common type of skin cancer?

Basal cell carcinoma.

What is squamous cell carcinoma?

Cancer of keratinocytes in the stratum spinosum.

What is the most deadly type of skin cancer?

Malignant melanoma.

What does the ABCDE rule stand for in skin cancer detection?

Asymmetry, Border irregularity, Color variation, Diameter greater than 6mm, Evolving.

What is a first-degree burn?

Affects only the epidermis; causes redness and mild pain.

What is a second-degree burn?

Affects the epidermis and part of the dermis; causes blistering.

What is a third-degree burn?

Involves the epidermis, dermis, and underlying tissues; may not be painful initially.

What tissues are affected by wounds?

Epidermis, dermis, and possibly deeper tissues.

What is acne caused by?

Accumulation of sebum and dead skin cells within sebaceous glands.

What cells are responsible for forming hair?

Keratinocytes in the hair follicle.

What is hair primarily composed of?

Hard keratin.

What is the purpose of nails?

Protection and tools for various functions.

What is the cuticle of the nail?

The eponychium, or skin at the base of the nail.

What is the hypodermis?

Subcutaneous tissue beneath the dermis.

What are the main components of the dermis?

Collagen and elastic fibers.

What role do adipose tissues play in the skin?

They provide insulation and energy storage.

What is the primary function of sebaceous glands?

To secrete oil (sebum) that lubricates skin and hair.

What is the primary immune cell found in the skin?

Langerhans cells.

What triggers melanin production in the skin?

UV radiation exposure.

What skin condition is characterized by uneven pigmentation and increased melanin production?

Freckles.

How can cell division lead to cancer?

Unchecked cell division creates tumors that can metastasize.

What factors contribute to the aging of the skin?

Decreased collagen, elastin, and fat tissue.

What do you call it when skin cancer spreads to other tissues?

Metastasis.

What action should be taken if a mole changes color or size?

It should be examined by a dermatologist.

What happens to hair and skin cells as they move away from the blood supply?

They die and become keratinized.

What is the most common way for bacteria to contribute to acne outbreaks?

By accumulating in clogged sebaceous glands.

Integumentary System

Consists of the skin and its accessory structures, including hair, nails, and glands.

Epidermis

The outermost layer of skin, composed of keratinized stratified squamous epithelium.

Dermis

The layer of skin beneath the epidermis, containing loose connective tissue and dense irregular connective tissue.

Hypodermis

Also known as the superficial fascia or subcutaneous fat; it anchors the skin to deeper structures. not a layer of skin! very vascular and composed of adipose and loose connective tissue.

Sebaceous gland

Glands that produce oily sebum to waterproof and lubricate the skin.

cellulite

A dimpled appearance of the skin caused by fat deposits pushing through the connective tissue beneath the skin, usually occurring in areas such as thighs and buttocks.(not a disorder)

Sweat gland

Glands that produce sweat for thermoregulation and excretion of waste.

Sensory receptors

Detect heat, cold, pain, and pressure in the skin.

Arrector pili muscle

Small muscles associated with hair follicles; cause hair to stand up (goosebumps).

Thermoregulation

The process of maintaining a stable internal body temperature.

Vitamin D synthesis

The process that occurs in the skin, where UV light converts dehydrocholesterol to vitamin D3.

Keratinocytes

The primary cell type in the epidermis that produces the protein keratin.

Melanocytes

Cells in the epidermis that produce melanin, the pigment responsible for skin color.

Dendritic cells

Immune cells located in the skin that protect against pathogens.

Tactile cells

Sensory receptors in the skin that detect light touch.

Stratum corneum

The outermost layer of the epidermis, consisting of dead, flattened keratinized cells.

Stratum lucidum

A clear layer of dead skin found only in thick skin areas.

Stratum granulosum

A layer of the epidermis where keratinization begins.

Stratum spinosum

Layer of the epidermis where keratinocytes are interconnected by desmosomes.

Stratum basale

The deepest layer of the epidermis, where cell division occurs.

Papillary layer

The upper layer of the dermis, which contains loose connective tissue and dermal papillae.

Reticular layer

The denser, deeper layer of the dermis; contains collagen and elastin fibers.

Melanin

The pigment produced by melanocytes that provides skin color and protects against UV damage.

Erythema

Redness of the skin often caused by increased blood flow.

Pallor

Paleness of the skin due to decreased blood flow.

Cyanosis

A bluish coloration of the skin due to low oxygen levels in the blood.

Jaundice

A yellowish coloration of the skin, often due to liver conditions.

Freckle

A small area of increased pigmentation due to melanin production.

Mole (nevus)

An area of increased pigmentation due to proliferation of melanocytes.

Albinism

A genetic condition characterized by the absence of melanin production.

Acne vulgaris

A skin condition that arises from an accumulation of sebum and dead cells in sebaceous glands.

First-degree burn

A burn affecting only the epidermis, causing redness and minor pain.

Second-degree burn

A burn affecting the epidermis and part of the dermis, causing blisters.

Third-degree burn

A burn that extends through the epidermis and dermis, affecting deeper tissues.

Basal cell carcinoma

The most common type of skin cancer, arising from keratinocytes in the stratum basale.

Squamous cell carcinoma

Skin cancer arising from keratinocytes in the stratum spinosum.

Malignant melanoma

A serious type of skin cancer that originates from melanocytes and can metastasize.

ABCDE rule

A guideline for identifying suspicious moles (Asymmetry, Border, Color, Diameter, Evolving).

Hair bulb

The base of the hair follicle where hair growth occurs through mitosis.

Hair follicle

The structure from which hair grows; includes epithelial and dermal root sheaths.